From 11385b2612004298ac2fbc9877e73f1410cfd3c0 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Wed, 2 Nov 2022 12:06:08 +0100 Subject: x86/uaccess: instrument copy_from_user_nmi() Make sure usercopy hooks from linux/instrumented.h are invoked for copy_from_user_nmi(). This fixes KMSAN false positives reported when dumping opcodes for a stack trace. Link: https://lkml.kernel.org/r/20221102110611.1085175-2-glider@google.com Signed-off-by: Alexander Potapenko Acked-by: Peter Zijlstra (Intel) Cc: Dave Hansen Cc: Kees Cook Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Marco Elver Cc: Masahiro Yamada Cc: Nick Desaulniers Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- arch/x86/lib/usercopy.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch') diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c index f1bb18617156..24b48af27417 100644 --- a/arch/x86/lib/usercopy.c +++ b/arch/x86/lib/usercopy.c @@ -6,6 +6,7 @@ #include #include +#include #include @@ -44,7 +45,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) * called from other contexts. */ pagefault_disable(); + instrument_copy_from_user_before(to, from, n); ret = raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, ret); pagefault_enable(); return ret; -- cgit v1.2.3-58-ga151 From ba54d194f8daad8943802d6dfe06e205f882c391 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Wed, 2 Nov 2022 12:06:11 +0100 Subject: x86/traps: avoid KMSAN bugs originating from handle_bug() There is a case in exc_invalid_op handler that is executed outside the irqentry_enter()/irqentry_exit() region when an UD2 instruction is used to encode a call to __warn(). In that case the `struct pt_regs` passed to the interrupt handler is never unpoisoned by KMSAN (this is normally done in irqentry_enter()), which leads to false positives inside handle_bug(). Use kmsan_unpoison_entry_regs() to explicitly unpoison those registers before using them. Link: https://lkml.kernel.org/r/20221102110611.1085175-5-glider@google.com Signed-off-by: Alexander Potapenko Cc: Borislav Petkov Cc: Dave Hansen Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Dmitry Vyukov Cc: Kees Cook Cc: Marco Elver Cc: Masahiro Yamada Cc: Nick Desaulniers Cc: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton --- arch/x86/kernel/traps.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch') diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 178015a820f0..d3fdec706f1d 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -301,6 +302,12 @@ static noinstr bool handle_bug(struct pt_regs *regs) { bool handled = false; + /* + * Normally @regs are unpoisoned by irqentry_enter(), but handle_bug() + * is a rare case that uses @regs without passing them to + * irqentry_enter(). + */ + kmsan_unpoison_entry_regs(regs); if (!is_valid_bugaddr(regs->ip)) return handled; -- cgit v1.2.3-58-ga151 From 1fdbed657a4726639c4f17841fd2a0fb646c746e Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Mon, 7 Nov 2022 11:10:10 +0900 Subject: arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The following bug is reported to be triggered when starting X on x86-32 system with i915: [ 225.777375] kernel BUG at mm/memory.c:2664! [ 225.777391] invalid opcode: 0000 [#1] PREEMPT SMP [ 225.777405] CPU: 0 PID: 2402 Comm: Xorg Not tainted 6.1.0-rc3-bdg+ #86 [ 225.777415] Hardware name: /8I865G775-G, BIOS F1 08/29/2006 [ 225.777421] EIP: __apply_to_page_range+0x24d/0x31c [ 225.777437] Code: ff ff 8b 55 e8 8b 45 cc e8 0a 11 ec ff 89 d8 83 c4 28 5b 5e 5f 5d c3 81 7d e0 a0 ef 96 c1 74 ad 8b 45 d0 e8 2d 83 49 00 eb a3 <0f> 0b 25 00 f0 ff ff 81 eb 00 00 00 40 01 c3 8b 45 ec 8b 00 e8 76 [ 225.777446] EAX: 00000001 EBX: c53a3b58 ECX: b5c00000 EDX: c258aa00 [ 225.777454] ESI: b5c00000 EDI: b5900000 EBP: c4b0fdb4 ESP: c4b0fd80 [ 225.777462] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010202 [ 225.777470] CR0: 80050033 CR2: b5900000 CR3: 053a3000 CR4: 000006d0 [ 225.777479] Call Trace: [ 225.777486] ? i915_memcpy_init_early+0x63/0x63 [i915] [ 225.777684] apply_to_page_range+0x21/0x27 [ 225.777694] ? i915_memcpy_init_early+0x63/0x63 [i915] [ 225.777870] remap_io_mapping+0x49/0x75 [i915] [ 225.778046] ? i915_memcpy_init_early+0x63/0x63 [i915] [ 225.778220] ? mutex_unlock+0xb/0xd [ 225.778231] ? i915_vma_pin_fence+0x6d/0xf7 [i915] [ 225.778420] vm_fault_gtt+0x2a9/0x8f1 [i915] [ 225.778644] ? lock_is_held_type+0x56/0xe7 [ 225.778655] ? lock_is_held_type+0x7a/0xe7 [ 225.778663] ? 0xc1000000 [ 225.778670] __do_fault+0x21/0x6a [ 225.778679] handle_mm_fault+0x708/0xb21 [ 225.778686] ? mt_find+0x21e/0x5ae [ 225.778696] exc_page_fault+0x185/0x705 [ 225.778704] ? doublefault_shim+0x127/0x127 [ 225.778715] handle_exception+0x130/0x130 [ 225.778723] EIP: 0xb700468a Recently pud_huge() got aware of non-present entry by commit 3a194f3f8ad0 ("mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry") to handle some special states of gigantic page. However, it's overlooked that pud_none() always returns false when running with 2-level paging, and as a result pud_huge() can return true pointlessly. Introduce "#if CONFIG_PGTABLE_LEVELS > 2" to pud_huge() to deal with this. Link: https://lkml.kernel.org/r/20221107021010.2449306-1-naoya.horiguchi@linux.dev Fixes: 3a194f3f8ad0 ("mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry") Signed-off-by: Naoya Horiguchi Reported-by: Ville Syrjälä Tested-by: Ville Syrjälä Reviewed-by: Miaohe Lin Cc: David Hildenbrand Cc: Liu Shixin Cc: Mike Kravetz Cc: Muchun Song Cc: Oscar Salvador Cc: Yang Shi Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Signed-off-by: Andrew Morton --- arch/x86/mm/hugetlbpage.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index 6b3033845c6d..5804bbae4f01 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c @@ -37,8 +37,12 @@ int pmd_huge(pmd_t pmd) */ int pud_huge(pud_t pud) { +#if CONFIG_PGTABLE_LEVELS > 2 return !pud_none(pud) && (pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT; +#else + return 0; +#endif } #ifdef CONFIG_HUGETLB_PAGE -- cgit v1.2.3-58-ga151